The focus of Dr. Halperin's research career has been extending basic and applied investigation to patient-oriented research. His work has been primarily in the fields of cardiopulmonary resuscitation and electrophysiology, where he continues to apply scientifically-based technology development to clinical medicine. He first studied the mechanisms whereby blood moved during cardiopulmonary resuscitation. That work led to the development of pneumatic vest CPR, which provides high-force circumferential chest compressions. After pre-clinical studies showed that pneumatic vest CPR improved blood flow and survival over that obtained with manual CPR, Dr. Halperin developed a clinical pneumatic vest CPR system, developed protocols for clinical studies, obtained FDA approval for the clinical studies, and published the results in the New England Journal of Medicine. Dr. Halperin's interests broadened from cardiopulmonary resuscitation to include electrophysiology, given that the arrhythmias that cause cardiac arrest are a major interest of electrophysiologists. A major limitation in studying arrhythmias in patients, however, is the lack of ability of current technology to accurately correlate anatomical and electrical information. Anatomy is derived from x-ray images, which are two-dimensional and have substantial anatomic ambiguity. Another major limitation is the lack of ability to visualize ablated areas of myocardium during catheter ablation procedures. Dr. Halperin has invented ways of combining the anatomic information from magnetic resonance imaging (MRI), with electrophysiologic testing and catheter ablation. After pre-clinical studies demonstrated the feasibility of performing MRI-guided electrophysiologic studies and catheter ablation, Dr. Halperin is extending this technology to patient-oriented research. Dr. Halperin has been awarded a Bioengineering Research Partnership grant from NHLBI to pursue this project, which is the current focus of his research. Dr. Halperin?s continued application of scientifically-based technology development to clinical medicine shows his commitment to patient-oriented research and his ability to perform that research. All technology has been sufficiently developed to allow the studies to proceed, but continued improvements will likely occur. This award would help free protected time to do these studies that would otherwise be used for performing standard clinical duties. By providing 50% salary support, this award would allow at least 50% of Dr. Halperin's time to be protected from standard patient care activities. That protected time would allow him more time to pursue the patient-oriented studies outlined in this proposal, and help train young clinical investigators.